Grease a six count mini Bundt pan with shortening. Set aside.
Peal peaches by hand over a bowl. Slice peaches, letting juices run into the bowl. Reserve 1 tablespoon of juice, set aside.
Place 1 tablespoon margarine in a non-stick pan over medium heat. Melt. Stir in sugar. Heat until well blended. Add sliced peaches and cook 5-7 minutes or until tender. Remove from heat and let cool for several minutes.
Place peaches in a small food processor or blender and puree. Set 1/4 cup of puree aside.
In a large bowl, beat butter in a large mixing bowl at medium speed with an electric mixer until creamy. Add granulated sugar and beat for 4 minutes. Add puree and beat until blended. Add eggs, one at a time, and beat until the mixture is thoroughly blended.
Combine flour, baking powder, and salt in a small bowl.
Add half of the flour mixture to butter mixture. Beat on low speed until blended. Add peach juice and blend on low speed until incorporated into batter. Add remaining flour and repeat blending.
Stir in vanilla and butter extract.
Batter yields 2 1/2 cup batter.
Pour batter into greased six count mini bundt pan.
Bake at 350 for 20-25 minutes or until set and a toothpick inserted into cakes comes out clean. Cakes will rise above pan.
Let cool 5-10 minutes before removing from pan. Cakes may be frozen once cooled. For best results, freeze individually.